• Journal of the Korea Safety Management & Science
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• v.14 no.3
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• pp.151-158
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• 2012

The objective of this paper is to propose a method of how to perform risk assessment in the early stage of defense research and development for the acquisition of weapon systems. An advanced method for risk assessment and its associated objective functions are developed first based on the concept of systems engineering. The developed method is then applied to carry out the analysis of alternatives in the trade-off environments. As a case study, the multi-purpose training ship is considered, where it is performed using the notions of technology readiness levels, degrees of difficulty, and technology need values to facilitate design space visualization and decision maker interaction. It is noted that decision makers can benefit from our approach as an improved risk assessment method in the context of multi-criteria decision making.

• Journal of Korean language education
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• v.29 no.4
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• pp.201-223
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• 2018

The purpose of this study is to observe the effects of text modification by comparing differences in Korean reading comprehension levels that arise from differences in vocabulary levels in texts. This study intends to use simplified texts with the vocabulary difficulty adjusted differently from the original text to measure reading comprehension levels of Korean learners and analyze the result. To measure reading comprehension, the researcher divided 55 Korean learners of intermediate to advanced level of fluency into two groups; the control group read the original text and the treatment group read a simplified text in which complex vocabulary were substituted with easier words of medium difficulty. Then the two groups were tested with the same questionnaire to measure comprehension levels of each group. The result showed that the groups that read simplified texts scored higher than the control group; this suggests that the reading comprehension level was increased in the treatment group. The experiment confirmed that unknown vocabulary density has direct impact on Korean reading comprehension. The result shows that the proportion of unknown vocabulary should be reduced for meaning-focused reading. It also demonstrates that comprehension of the learner was enhanced with lexical simplification rather than structural simplification i.e. simplification of grammar or sentences. Thus, diverse reading materials adjusted to the learners' level of fluency should be developed to enable reading for learning Korean. By reducing the burden of understanding the meaning of each vocabulary, learners will be able to achieve the initial goal of reading.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.145-152
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• 2015

In this study, PASW Statistics ver. 18.0 was used to analyze the correlation between chewing difficulty and osteoarthritis in the population of 8,498 persons aged 50 years and older who had completed the health related questionnaire in the fifth Korea National Health and Nutrition Examination Survey in 2010~2012. The following conclusion was drawn: The distribution of the chewing difficulty status showed that 38.8% of the respondents had chewing difficulty and that there was no significant difference by gender. Older respondents tended to have significantly greater chewing difficulty 34.3% of the respondents aged from 50 to 64 years and 46.4% of those aged 65 years and older, those who had lower levels of education and income, who were smokers, and who had higher levels of depression and stress suffered from significantly greater chewing difficulty. Chewing difficulty and osteoarthritis were correlated with each other: the respondents having chewing difficulty had 1.44 (95% confidence interval [CI], 1.23~1.70) higher prevalence of osteoarthritis than those with no such difficulty. In addition, such correlation was not found in males: the former had 1.36 (95% CI, 0.98~1.88) higher prevalence of osteoarthritis than the latter, which was not statistically significant. Such correlation was found in females: the former had 1.47 (95% CI, 1.22~1.76) higher prevalence of osteoarthritis than the latter, which was statistically significant. Therefore, the chewing difficulty status affected osteoarthritis for females aged 50 years and older. Therefore, the efforts to solve oral health problems through oral hygiene would help prevent osteoarthritis from worsening and manage the condition.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.334-344
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• 2020

This study explored students' subject interests and task difficulty recognition levels changed when they provided tasks with Keller's ARCS motivation design in PBL(Problem Based Learning) class. This study participant were 79 college students majoring in teaching profession. Experimental and comparative groups were formed for the study. Primary PBLs were conducted to measure prior levels of subject interest and task difficulty recognition. Secondary PBLs were performed to verify the effectiveness of the ARCS motivation design task. The experimental group performed the tasks that reflected the ARCS motivation design. Collected data were analyzed using ANCOVA. As a result, the experimental group had a higher level of subject interest and a lower level of task difficulty recognition.

• Journal of Korea Game Society
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• v.15 no.4
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• pp.169-178
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• 2015

Providing various levels of difficulty of game play is one of important considerations in game development. In this paper, we propose a method for obtaining the challenges that will be placed on the track of an one-player car driving game. Herein challenges denote obstacles on the track, and the level of difficulty is represented by an estimated time needed for driving one lap of the track. In the proposed method, the problem for finding challenge placement is modeled as an IP(Integer Programming) one, and then LP relaxation and Simultaneous Annealing are employed to find a solution. To the experiment with the proposed method, we can obtain challenge placements to approximately meet given target driving times. Also, after practically driving on the track where those obtained challenges are being placed, it is seen that the average driving times approximate the target driving times of those challenge placements. Our method can allow game play with various levels of difficulty so that the users' interest and the level of immerse are expected to be raised.

• Physical Therapy Korea
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• v.18 no.3
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• pp.59-66
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• 2011

The purpose of this study is to examine the activity ratios of global trunk muscles and local trunk muscles in relation to adjustments in the level of task difficulty while performing stability exercises in easily applied bridging lumbar stabilization exercise. Twenty healthy subjects performed bridging lumbar stabilization exercise while the level of task difficulty was plate was used in the same posture for all the exercises. EMG was used to examine the activity ratios of the global muscles and multifidus in relation to the level of task difficulty. Moreover, the activity ratios of the multifidus muscle, the erector spinae and the gluteus maximus muscle were measured. A one-way ANOVA with repeated measures was used, and a Bonferroni correction was conducted (${\alpha}$=.05). When the bridging lumbar stabilization exercise were performed at different difficulty levels, the activity of the multifidus muscle, which is a local muscle, was high in all three exercises. Also, compared to low intensity and intermediate intensity exercises, high intensity exercises showed more significant differences (${\alpha}$=.05). Among all the muscles, the multifidus showed the highest activity at intermediate intensity. Based on these results, we suggest that in the case of bridging lumbar stabilization exercise, low intensity or intermediate intensity exercises are more suitable and efficient for local muscle stabilization.

• The Journal of Health Technology Assessment
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• v.6 no.2
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• pp.100-105
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• 2018

Objectives: The purpose of this research is to investigate regional variations of mastication difficulty rates in the elderly over 65 in 229 primary autonomous districts in Korea and explore relevant characteristics. For the research data, local community health survey conducted in 2015 and data from Ministry of the Interior and Safety, Ministry of Health & Welfare, National Health Insurance Service and Statistics Korea were used. Methods: Frequency analysis was conducted for general characteristics and mastication difficulty rates of each region, and distribution of mastication difficulty rates was displayed for each town, city and province by mapping them. Extremal quotient (EQ), coefficient of variation (CV) values were calculated for regional variations, and logistic regression analysis was performed to reveal the relationship between each independent variable and mastication difficulty rates. Results: The average of standardized mastication difficulty rate was 46.78%, and regional variations were significant with EQ 3.46, CV 0.18. Characteristic factors that have significant effects on mastication difficulty rate included sex ratio, elderly population and the number of dentists per 10000 people. Conclusion: As a result, there were variations among mastication difficulty rates in 229 primary local governments across the country, and the distribution of health care resources by the characteristics of the local environment by region affected mastication difficulty rates. Accordingly, it is required to provide political supports to overcome regional inequality of oral health levels and develop cooperative system between local governments and local dentists.

• Journal of the Ergonomics Society of Korea
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• v.23 no.3
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• pp.101-109
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• 2004

This paper reports the results on age and gender of Korean elderly people for the level of difficulty in performing household tasks (meal preparation, grocery shopping, house cleaning, laundry), personal tasks (dressing, bathing, grooming), transfer tasks (getting in and out of chairs, getting in and out of bath-tub, using stairs) and management tasks (using telephone, accessing mail, operating door locks). A questionnaire based on the Activities of Daily Living (ADL) scale was constructed and administered to 40 Korean elderly subjects aged from 65 to 84(mean age: 74.5, SD: 5.8) in Busan. Additionally, a logistic regression was performed with age (continuous variable) and gender as predictor variables, and reponses to individual questions as the categorical ordinal response variables. To determine appropriate age separation at which difficulty levels in performing activities of daily living change, a discriminant analysis was performed on the responses. All predictor variables were used in the analysis. Accommodating age related changes in functional abilities, and increasing functional independence of elderly people will entail significant design modifications to products, systems and environments for daily use and living.

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.306-310
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• 2009

The purpose of this study is to observe the change in gamma-band cortical activities (GBAs) due to task difficulty. Event-related potential and gamma-band activity were investigated using electroencephalograms recorded during auditory oddball tasks with two difficulty levels. For more difficult task, the amplitude of P300 decreased and the peak latency of P300 was delayed significantly compared to easier task. The induced GBA decreased considerably during the P300 latency period and the peak latency of the induced GBA was delayed for more difficult task. The results imply that the difficulty-related change in cortical information processing may be implemented as a change in the strength of local neuronal association.

• International Journal of Advanced Culture Technology
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• v.11 no.2
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• pp.210-220
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• 2023

We analyzed and compared factors such as changes in the degree of difficulty of concepts presented in Chemistry I textbook, changes in class types (non-face-to-face, face-to-face), etc. on academic achievement by level (upper, middle, and lower). Students from A high school in Gyeongsangnam-do were selected for the subjects of the study. As a result of analyzing the change in the degree of difficulty of concepts, the total score of chemistry I combined by non-face-to-face and face-to-face classes during the second semester was lower than that of the first semester. As a result of analyzing the impact of factors such as changes in conceptual difficulty, changes in class types, etc. on academic achievement by level, students' grades at the 'lower level' by non-face-to-face classes were lower than those by face-to-face classes. In particular, at the lower level of the second semester, there was a large difference in grades between non-face-to-face and face-to-face classes. In the results of these studies, it was found that instructors' active feedback is important to identify difficulties in understanding learning contents for students with low levels of academic achievement and improve them at the same time.